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Ffield Handler

ReaxFF force-field parameter (ffield) handler.

This module provides a handler for parsing ReaxFF ffield files, which define all force-field parameters used in ReaxFF simulations.

Unlike most handlers, ffield data is inherently sectional rather than tabular and is therefore exposed through per-section tables instead of a single summary DataFrame.

FFieldHandler

Bases: BaseHandler

Parser for ReaxFF force-field parameter files (ffield).

This class parses ReaxFF ffield files and exposes all force-field parameters as structured, section-specific tables suitable for inspection, modification, and analysis.

Parsed Data

Summary table The main dataframe() is intentionally empty for ffield files. All meaningful data is stored in per-section DataFrames.

Section tables Accessible via sections or section_df(name), with one table per force-field section:

- ``general``:
  Global ReaxFF parameters (39 fixed parameters), columns:
  ["index", "name", "value", "raw_comment"]

- ``atom``:
  Atom-type parameters, indexed by atom number, with columns:
  ["symbol", <atom parameter names>]

- ``bond``:
  Bond parameters, indexed by bond index, with columns:
  ["i", "j", <bond parameter names>]

- ``off_diagonal``:
  Off-diagonal interaction parameters, indexed by entry number, with columns:
  ["i", "j", <off-diagonal parameter names>]

- ``angle``:
  Angle parameters, indexed by angle index, with columns:
  ["i", "j", "k", <angle parameter names>]

- ``torsion``:
  Torsion parameters, indexed by torsion index, with columns:
  ["i", "j", "k", "l", <torsion parameter names>]

- ``hbond``:
  Hydrogen-bond parameters, indexed by hbond index, with columns:
  ["i", "j", "k", <hbond parameter names>]

Metadata Returned by metadata(), containing counts per section: ["n_general_params", "n_atoms", "n_bonds", "n_off_diagonal", "n_angles", "n_torsions", "n_hbonds"]

Notes
  • Parameter names follow canonical ReaxFF ordering and numbering.
  • Unused parameters are labeled n.u. with numeric suffixes.
  • Inline comments in the original file are preserved where applicable.
  • Section headers and ordering are detected automatically.